1. Field of the Invention
The present invention relates to a method of producing alcohol compounds, and more particularly, to a method in which an alcohol is used as a reducing agent for reducing carboxylic acids or esters thereof so as to produce corresponding alcohol compounds.
2. Description of the related art including information disclosed under .sctn..sctn.1.97-1.99
A reaction for converting a carboxylic acid or an ester thereof into its corresponding alcohol involves conversion of functional groups, which is important in the chemical industries. The known methods for the conversion include, for example, a method using a dissolved metal and a method of heterogeneous catalytic hydrogenation. A method using a hydride such as boron hydride or aluminum hydride or a derivative thereof as a reducing agent is also known to the art.
The method using a dissolved metal permits producing alcohol compounds at a relatively low cost and, thus, is widely employed. However, an active metal such as lithium or sodium is used in this method, making it necessary to handle the active metal very carefully. For example, these active metals vigorously react with water to generate hydrogen gas which is ignited easily. In addition, the method necessitates troublesome steps of treatment with water and extraction with an organic solvent for the recovery of the reaction products.
In the heterogeneous catalytic hydrogenation method, used is, for example, a ruthenium-based catalyst, a copper chromite-based catalyst or Raney nickel catalyst. However, a relatively high temperature/high pressure is required and the carboxylic acids/esters as the starting materials are restricted in this method, as described in, for example, "Reduction in Organic Chemistry" by Hadry.
The method using a hydride as a reducing agent can be widely used. However, the reducing agent used is costly and highly reactive with water, making it necessary to handle and preserve the reducing agent carefully. Also, the reaction in this method is generally so vigorous that the hydrogen gas produced in the reaction may possibly be ignited. Further, the method requires troublesome post-treatments to decompose the complex formed as an intermediate product and to extract the decomposed substances with an organic solvent.